It is estimated that the energy released through combustion of only about 20 percent of the fuel introduced to a carburetor is converted to useful mechanical energy, the remaining 80 percent being wasted. It is, accordingly, an object of the present invention to provide a fuel inlet system by which the major part of the remaining 80 percent of fuel introduced into a carburetor is used in the combustion process to provide useful energy, thus significantly improving the fuel efficiency of an internal combustion engine.